topic Re: throughput and IOPS in CLARiiONhttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729376#M18344
<HTML><HEAD></HEAD><BODY><P>The context of that statement is in actually measuring IOPS...&nbsp; What they are saying is that the number of I/Os processed per second is a measurement of it's own and is not dependent on the size of the IOs themselves.&nbsp; ie: 1000 IOPS @ 4KB = 1000 IOPS, 1000 IOPS @ 32KB still = 1000 IOPS.&nbsp; As IO size varies at a given IOPS, bandwidth will be affected.</P><P></P><P>Where IO size matters is as size climbs over 16KB and into the 64KB+ territory, the maximum number of IOPS sustainable by a given storage system will decrease.&nbsp; ie:&nbsp; IOPS and Bandwidth are inversely proportional.</P></BODY></HTML>Tue, 11 Jan 2011 07:00:33 GMTStoragesavvy2011-01-11T07:00:33Zthroughput and IOPShttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729375#M18343
<HTML><HEAD></HEAD><BODY><P>in EMC CLARiiON Storage System Fundamentals for Performance and Availability, page 29. it says: This measurement（of IOPS） is independent of request size</P><P>so, what's the unit of IOPS. in my opinion, the IOPS is very dependent on the IO size.</P></BODY></HTML>Tue, 11 Jan 2011 03:57:34 GMThttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729375#M18343dingding12011-01-11T03:57:34ZRe: throughput and IOPShttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729376#M18344
<HTML><HEAD></HEAD><BODY><P>The context of that statement is in actually measuring IOPS...&nbsp; What they are saying is that the number of I/Os processed per second is a measurement of it's own and is not dependent on the size of the IOs themselves.&nbsp; ie: 1000 IOPS @ 4KB = 1000 IOPS, 1000 IOPS @ 32KB still = 1000 IOPS.&nbsp; As IO size varies at a given IOPS, bandwidth will be affected.</P><P></P><P>Where IO size matters is as size climbs over 16KB and into the 64KB+ territory, the maximum number of IOPS sustainable by a given storage system will decrease.&nbsp; ie:&nbsp; IOPS and Bandwidth are inversely proportional.</P></BODY></HTML>Tue, 11 Jan 2011 07:00:33 GMThttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729376#M18344Storagesavvy2011-01-11T07:00:33ZRe: throughput and IOPShttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729377#M18345
<HTML><HEAD></HEAD><BODY><P>Actually it's the other way around: IOps varies as I/O size varies. IOps is a dynamic value, I/O size is a fact. If I/O size goes down, IOps goes up. And between 32kB or 1kB there's absolutely a difference in IOps.</P></BODY></HTML>Tue, 11 Jan 2011 13:01:27 GMThttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729377#M18345RRR2011-01-11T13:01:27ZRe: throughput and IOPShttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729378#M18346
<HTML><HEAD></HEAD><BODY><P>Knowing the author, I can confirm what his intent was. But I think he caused some confusion.</P><P></P><P>The <EM>measurement</EM> of IOPS is IO size agnostic. E.g., If I am doing 1000 IOPS at 8 KB, or 1000 IOPS at 32 KB, I'm still doing 1000 IOPS. A pound of lead weighs the same as a pound of feathers.</P><P></P><P>The <EM>performance of a system</EM> when using IOPS as a measurement is dependent on the IO size. So, if my machine has the capability of performing 1000 IOPS at 8 KB, it is unlikely to have the capability of doing 1000 IOPS at 32 KB. My car can do 150 Kilometers per hour but only 90 Miles per hour.</P><P></P><P>The conversion from MB/s to IOPS <EM>is</EM> dependent on IO size. This is a linear relationship. 1000 IOPS at 8 KB is (1000 * 8 )/ 1024 MB/s = 7.8 MB/s</P><P>However 1000 IOPS at 1 MB IO size is 1000 * 1 = 1000 MB/s</P></BODY></HTML>Tue, 11 Jan 2011 17:44:19 GMThttps://www.dell.com/community/CLARiiON/throughput-and-IOPS/m-p/6729378#M18346DaveZ12011-01-11T17:44:19Z